Armored insulating-conduit.



Patented Ian. 30, I900.

A.-THOMA. ABMORED INSULATING CONDUIT.

(Application filad July 29, 1899.)

(No Model.)-

Nr'rnn des res Farrier ANDREN TITOMA, OF CAMBRIDGE, MASSACHUSETTS, ASSlGllOlt 'l() AMANDA M. LOUGEE, OF BOSTON, MASSACHUSETIS.

ARMOREU lblSULATlNG-OGNDUET.

SPECIFICATION forming part of Letters Patent No. 642,538, dated January 30, 1900.

Application filed July 29,1899- i l No- 725,58'7. (No model.)

To coll mil/0172, it may concern:

Be itknown that LANDREW THOMA,Of Cambridge, county of Middlesex, State of Massachusetts, have invented, an Improvement in Armored Insulating-Conduits, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

In the installation of electric Wires and for many other purposes it is necessary to utilize a conduit or pipe which shall possess insulating properties to a high degree, shall resist chemical and mechanical injury, shall be indestructible by'a considerable degree of heat or moisture, and which shall be capable of ilexure without injury and without deterioration with respect to any of the properties set forth. In such conduit the inner diameter must be as large as possible consistent with proper provision for insuring the various properties noted, must be simple in construc-.

tion, and inexpensive.

Various conduits have been placed upon the market from time to time; but none of these embody the properties essential to a satisfactory conduit, and in order that my invention may be readily understood audits value appreciated I will indicate briefly some of the particulars in which prior conduits have been found wanting.

Various linings. or inner tubes have been utilized to-give properties of insulation and 'moistureproofing to the conduits, and much efiort has been expended in the attempt to adapt paper to this purpose, but without com- 'plete satisfaction, for the especial reason, among others, that the paper is lacking in the requisite degree of strength and almost 40 completely wanting in flexibility. In fact, rigid tubes, Whether of paper, wood, or other fibrous material, are open universally to this objection and to the additional objection that i t'is dil'licultto unite them properly to the armor tube. Furthermore, inner tubes, whether united directly to the armor or I whether an intervening bindingagent of considerable thickness is employed, diminish the inner diameter of the conduit to an undesirable extent. 'loavoid this diminution and still provide for, suitable adherence to the armor-tube, linings of oil-cloth and other fabrics have been employed and to a certain extent a tube'of larger working diameter has been obtained, but even with these the tube is stillbulky in many instances, and a fabric whenever used exhibits a constant tendency to pull away from the walls of the armor-tube, provided the fabric is strong-enough to retain its integrity under the bending strain; but very frequently the temperature applied in securing-adherence of an oil-cloth or similar lining, and the very natnre'of the ma: terials, renders the fabric liableto a great weakening, so that its rupture ensues upon 6; fiexure'of the conduit. The evil effects and possibilities of such displacement or rupture of the inner member of the conduit are too Well known to require setting forth in detail.

In a conduit which has been provided with a lining of oil-cloth next to the armor and a lining of paper inside the oil-cloth the effect has been to have the paper mechanically hold the oil-cloth after bending against the tendency to pull. away from the walls of the armortube, but the paper tube itself, byreason of its non-extensibility, is invariably ruptured in one or more places transverse to the length of the conduit.

The gas-pipe of commerce affords a cheap and satisfactory armor member, but is irregular in internal diameter, and the usual stilt iusulating-tubes,of paper, wood,oil-cloth, rubber vulcanized hard, and thelike, have barely approximated the inner diameter of the armor, not conforming to'its contour in a manner permitting proper union, so that when bent cold failure of the union or fracture of the insulating member has been universal. This tendency has been augmented by'the presonce of asphalt or residuum of petroleum between the members of the conduit introduced in an unsuccessful attempt to fill up the spacesleft by the irregularity of the pipe and by reason of its brittle nature when cold g breaking up under bending strain. Such a substance thus introduced as a filler inbulk has but little cementitious quality and is a detriment rather than an aid to union, while moisture will collect in the spaces where it x has failed to penetrate and increase the separation of the members, with destructive chemical effect as well. l

The great difficulty encountered in produc ing successful conduits of the type noted above and their prohibitory expense, whether satisfactory or not, has favored the introduction to a considerable extent of pipes without inner tubes or linings other than acoating of japan applied to the walls,an expedient which leaves a maximum diameter and reduces the bulk of the pipe, but utterly fails to meet the moisture, insulation, and other tests to which the best conduits should'be and are subjected,

leaves also much to be desired in point of' flexibility, and which is unequal to the demands of permanence and resistance to rough handling and manipulation in installation, as also are other more coa ingsdepositod from solutions. V

In general conduits at present on the market if they are suificiently flexible lack proper capability of resistance to mechanical and chemical injury, while those possessing due resistance in the latter respects are not capable of flexure without injury. To remedy these defects and produce a conduit which shall meet the stringent requirements of the electrical art and be available for many other purposes as well, I employ for mylining material or insulating member a composition of matter, th us avoiding the structural deficiencies of a fabric, and by the use of suitable ingredients I can secure in a degree heretofore unattained in a lining material the extensibility and high flexibility so requisite in an armored conduit subject to liexure when cold. As manipulation of ahighly-flexible insulating member of such a character within ten, fifteen, ortwenty, foot lengths of pipe of small diameter is almost impracticable by ordinary methods, especially if coated thoroughly with a cementitious substance of suitable adhesive qualities, I have devised a support by means of which the introduction of the flexible material can be accomplished with facility and which is withdrawn after assemblage of the members of the conduit, the same forming the subject of a'separatc application, Serial N 0. 728,391, filed August :34, 1809. As above noted, a composition of matter may be made of such flexibility as to conform exactly to the contour of the armor, and to secure it permanently in shch relation use may be made of any suitable cementitious substance, and an example of one such cementitious sub stance, exhibiting high capacity of adhesion to the armor and equal affinity for the flexible insulating composition, is disclosed and claimed in an application filed by me June 15, 1899, Serial No. 720,360.

Existing methods of applying the insulat ing member having proved inadequate in many respects, I have devised a method in which after the insulating material has been inserted within the armor-tube a free blast of air or the like is projected through the same to act progressively upon and within the insulating material throughout, and I have in the present specification used this as illustrative of a convenient method of assemblage; but I do not claim said method broadly in the present application, having made it the subject of generic claim in my application, Serial No. 697,833, filed November 30, 1898.

It will be understood that Ivdo not restrict myself to the use of my novel conduit for electrical purposes, but contemplate its utilization in any field where it may be used to advantage.

The various features of my invention will be illustrated and described fully in the accompanying drawings and specification and set forth in the claims.

In the drawings, Figure 1 is a view in side elevation of a short-length of conduit in the construction of which myinvention has been utilized, Fig. 2 being a view in transverse section of the same.

My novel conduit comprises an armor-tube and an inner insulating member of an extensible and highly-flexible composition of matter united adhesively to the inner walls of the armor so thoroughly as to make pos- 5 sible its support wholly by said adhesion and permit flexure of the conduit when cold or, -on the job without impairment of the union or of the insulating properties of the insulating member. flexible insulating member may be of any material possessing the qualities requisite to this end, and their union may be effected and maintained by any suitable means, A convenient armor is yielded by the well- 105 known gas-pipe of commerce, which can be provided with its insulating member not only in the ten-foot lengths, beyond which the manufacturer rarely, if ever, ventures at the present day, but by my improved methods I no am able to treat profitably lengths running up to twenty feet and yield aproductof such flexibility as. to diminish remarkably the quantities of elbows required in installations hitherto, accompanied as they are by undue I I5 labor charges, While mostsubversive of good continuous insulation.

One example of a composition of matter possessing a high degree of flexibility, and

therefore of great utility as a lining for my 120 novel conduit, forms the subject of my application, filed June 13, 1899, Serial No. 720,360, in which is a full disclosure of said composition, in place of which, however, use may be made of any composition possessing x2 5 in suitable degree the qualities set forthabove. 7

By the term insulating it will be understood that I do not mean to imply that my conduit is of use only for purposes of con- :30

The armor-tube and can be elfi ected with ease and efiicie'ncy by permanency of union may be efiected, or use may be. made of such methods and means as are found suitable to secure the desired end.

In the drawings the armor member is designated by the reference-letter A, the insulating member by the reference-letter B,- and the cementitious substance by the referenceletter C.

By avoidance of fabrics and the use of an insulating composition having qualities of extensibility and high flexibility equal to that devised by me, to which I have referred above, and by utilizing efiicient methods of introducing, applying, anduniting the lining member, as my methods to which I have referred also, the conduit of this present application is provided with a lining in exact conformity with the inner walls of the armor throughout their adjacent surfaces. Furthermore, in the conduit constructed according to my invention and illus 'ted it will be noted that the perfect t r yii un nhetween the members provides for the support of the insulating member wholly from the inner walls of the armor member, so that the thickness of the insulating member is not such as either to reduce the effective diameter of the conduit or to interfere with its flexibility. .In-

deed, the completed conduit may be bent cold with perfect impunity, affording a distinct advance over conduits as constructed in accordance with the present state of the art.

Having descnibed my invention thus fully, I wish it understood that I do not limit myself to the exact details of construction or materials illustrated and described nor in general otherwise than as set forth in the;

- claims.

Having 'deshrib'ed my invention, what I claim, and-desire to secure by Letters Patent, 1s-

1. An armored insulating-conduit consist ing of an armor-tube, and an inner lining of an extensible, highly-flexible composition of matter id'intimate contact with the inner walls of said tube at eyery point-throughout the area of their adjacent surfaces.

2. An armored insulating-conduit; comprisi'ngan outer armor-tube of heavy iron pipe; a'liningof an extensible, highly-flexible composition of matter, in intimate contact with the inner walls of said tube at every point throughout the area of the adjacent surfaces of said tube and lining; and means to secure adhesion of the former to the latter throughout said area, substantially as described.

3. An armored insulating-conduit consisting of an armor-tube and an inner ply of an extensiblehighly=flexible composition of matter conforming exactly to the contour of, and supported wholly by adhesive union with, the inner walls of said tube, said conduit being capable of flexure without disruption of said union.

4. An armored insulating-conduit comprising an armor tube and an-inner-insulating member of an extensible highly-flexible composition of insulating material supported wholly by adhesive union with the inner walls of said armor-tube, said conduit being capable of flexure when cold, without impairment of said union or of the insulating qualitiesof said insulating memben' In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

. ANDREW THOM Witnesses:

ALEXANDER O. PROUDFIT, FREDERICK L. EMERY. 

